Big Question wanting to hear some feedback

So, here's my dilemma. I have this vision for a story. The premise is that our Protagonist, who has dreams of being an actor, has sex with the person running an audition. It's consensual, and both parties enjoy it. After a wham, bam, thank you, ma'am; both parties go their separate ways. But, this one-night stand turns into a love song which will be my tale. So, here's the million-dollar question. "How graphic should this sex act be?" I want to hear your honest opinions, please.